Poly(arylene sulfide) polymers are generally known in the art and are employed in a number of applications due to their high temperature and chemical resistance and good electrical and mechanical properties. Poly(arylene sulfide) polymers are used in the preparation of fibers, films, coatings, injection molding compounds and fiber-reinforced composites.
Impurities in the poly(arylene sulfide) polymer can contribute to certain processing and product problems. Problems include off-gassing, injection mold plate out and corrosion of processing equipment used in injection molding applications. Problems can also include poor adhesion to substrates for coatings and poor adhesion to reinforcing fibers in composites.
It is thus desirable to reduce the amount of impurities in the poly(arylene sulfide) polymer. One method of accomplishing this has been to treat the recovered polymer with an acidic solution. This, however, results in the inclusion of an extra wash and recovery step.
The poly(arylene sulfide) polymer is generally prepared in a reaction employing at least one sulfur-source, at least one dihalogenated aromatic compound and a polar organic compound, optionally with molecular weight modifying agents such as alkali metal salts. The reaction mixture is very basic, contributing to corrosion of the metal contacting the mixture. Certain by-products are formed during the reaction which chemically bind the polar organic compound and render recovery and reuse of the polar organic compound difficult. It would therefore be desirable to have a method for rendering the reaction mixture less basic and for causing the by-products to release the polar organic compound.